Blow mold machines having a rotatably driven heating wheel and a rotatably driven blowing wheel are well-known in which parisons positioned on mandrels or pins are carried on a heating wheel pass heating means such as radiators to be heated up to blowing temperature. They are subsequently taken out by means of a transfer device and delivered on to the blowing wheel on which the parisons are enclosed between a pair of blow mold portions and blown to the final article. The dimensions of the shape of the blow mold portions and the actuating means associated therewith result in relatively large peripheral distances of the mandrel receiving positions on the blow wheel. These peripheral distances determine the pitch of the wheel. Accordingly, the blow wheel is a wheel having a large pitch.
If one selects the pitch of the heating wheel to be identical to the pitch of the blowing wheel, the transfer from the heating wheel to the blowing wheel is very simple. However, a large pitch of the heating wheel is not desirable as the diameter of the heating wheel must be substantially increased to allow heating a certain number of parisons to the desired blowing temperature which number is determined by the blowing conditions on the blowing wheel. Therefore the mandrels on the heating wheel are spaced at very small peripheral distances. From this, it follows that the heating wheel is a wheel having a small pitch.
From this in turn, it follows that the transfer device between the heating wheel and the blowing wheel must compensate for the different pitch sizes of both wheels. In other words, the transfer velocity of the transfer device must be delayed after taking out a mandrel of the heating wheel to deliver the mandrel into the next following mandrel receiving position of the blowing wheel. Subsequently, the return velocity of the transfer device to the heating wheel must be accelerated. This requires a substantial structural complication of the transfer devices including rotatable and cam controlled transfer arms for example.